Process of preparing azodyestuffs



` c 135 l analytical chemistryfor isolating heavy metals; per can beremoved.

Patented Mar. 26, 1935 l v l UNlrlazDi-.Snrls1PMENToFFIC?A f I signor toGeneral Aniline Works, Inc.,"New `jrork, N. Y., a corporation ofDelaware NoDrawing. Application ,November 10j, 1119,32, l

Serial No. 642,126. In Germany yNovember 13,` 1931 v '6 Claims, (o1.2602-94) `The present invention relates to a process of in hydrochloricacid`r solution, Vthere can be prepreparing azodyestuffs capable ofyielding heavy cipitated from thev dyestuis all those metals metalcomplex compounds. l l known in analytical chemistry as hydrogen sul- Itis knownv from'the literature that azodyende group, such as copper,lead, cadmium, while, i 5 `stuffs which are characterized Y by having'hywhen working in alkaline solution, either in causdroxy groups in vthep oopositions tov at least tic alkaline-,in bicarbonateo-r in carbonatevsoone azo group, or an amino group or an alkyllution, there can beprecipitated'generallythose or aryl-substituted amino group 'and' ahydroxyV metals. known in analyticalchemistryl vas-l amgroup, orl acarboxylic acid kor carbonyl `group monium sulde group.Av In thismanner, for ex- 10; anda hydroxy group or amino group which may ample,iron, manganese, nickelfcobalt, and also 10 likewise be substituted byalkyl* or arylfgroups, metals Of the hydrogen Sullide group, may be orwhich contain inthe molecule a hydroxy group precipitated, whilechromium which does not and a carboxylic acid group in o-position toeach form a stable sulde cannot be` precipitated 'as other can betransformed into heavy metal coma sulfide. The `preferred agent" ofprecipitat- 15 poundsl containingV the heavy metal in a coming heavymetals aoool'dng' to' this method is '15 plex form. As heavy metalscombining lwith sodium sulfide, 'it being self-understood.- thatVazodye`.stuiis to form complex compounds there other suldes may be usedwith the same result'.l

may be mentioned by Way of examp1e,llead,bis jWhen precipitatingA theheavy metalsA asjsulmuth, cadmium, copper, Zinc, chromium, nickel, fidesby means ofv hydrogen lsuliideor a ,salt .120 `cobalt, iron, manganeseand the like.V thereof it should be borneuin mind that' hydrogen-20 Inaccordance with my present invention azok vsuliide is a strong reducingagent andthat in dyestufs capable of yielding heavy metal com- Subjectngsuchmdyestuis 'which contain groups plex compounds are prepared `bystarting with liable to undergo'reduction,respecially the nitro thecorresponding azodyestuis containing a group,ithesegroups are reduced bythe hydrogen 25 heavy metal in a 'complex form and removing"sul1"ide.ly'l f said heavy metal by treating the dypestuff with j stated above theheavy metals may befuran agent capable of combining 'withthe heavy `therremoved from the azodyestuffs by treating metal attached to theazodyestui in a complex4 the dyestuffs with a compound,yieldingajcomform, plex compound with the heavy metal and having f1 305,', Thespecific method of removing the heavy `a strongerfainity to the samethan the "azo- 30 metal fromthe azodyestuff depends on thespedyestufffsuch compounds 'are for example, or-

cic heavyfmetal to be, removed.v As a-general ganic polyhydroxycompounds, especially acids, rule 'may b'effstated that there come into'con- 1 such as oxalic acid, tartaric acid and citric acid. siderationallv those methods generally used in In this manner, for example,chromium and cop- H35 for example, the heavy metaljmay be preop- Thethird method referred to? above consists tated in formof a dicultlysoluble compound, in treating the heavy'metal 'complex compounds or theheavy metal Complex Compound ofthe. of the azodyestuffs with e. strongacid, forexazodyestui may be Greaod With a Suitable 09mample, with .aconcentratedo-r aqueous dilutesul- 40 Pound! yielding a Complex CompoundWWP the furie-6r hydroohlorioacidor also withformic 40 4 lloaVy metalafndvlfllflngk a Stronger .afmty to, acid. 'f 'TheV temperaturesrequired somewhat de- .SaldheafW meta/l than the a'zodyestu; 01 nal ypend uponA the concentration of the acid used'in ly, in vsome 'cases the.heavy metal attached to the such a manne that a`z`odyestuffsin'acomplex form `can be'splitpi r" lower concentratlonsreqmreAlfbytreang the dyestuffwth an acid. l K. higher temperatures, andvlceversa. Thus, for 45 .t Y e r ro example, ywhenuslng an aqueous sulfuricacid,

' duihneg ylgf lealyvmgal gom, such Yas a 30% sulfuricaeidgenerallyheating is *t the* Samern al Cumplex formonsinsbsin necessary, forexample, at a temperature between 'preeipitating'the-heavy mei-,a1 asadifeuiuy soin- 1 about '15 Q- and about the bo111ng pomt of the blecompound, preferably in form of,asulde', ractlon mmture- 'A prferredmethod 0f Peri-50 for example, by treating the ezodyestui in susformingthe process oonslsts in introducing ythe pensionv oir-.solution withhydrogen sulfide in `.heavykvmetal containing azodyestuffs into conacid'se1utienj or with a. suitable sulfide in alka.- Yoentrated sulfuricacid of room temperature, line solution.` y.wherein the dyestuidissolves with the split- 'meng working in acid solution, for exampletingo of the heavy metal. According to this'f method chromium, copper,lead, iron, nickel, cobalt and the like can be removed.

According to my new process there are obtainable azodyestuffs capable ofyielding heavy metal complex compounds which are not obtainable or onlydifficultly obtainable according to other methods. Thus, forexample,.the o-hyi droxyazodyestuii' according to the following; Ex-

ample 1 cannot be prepared by coupling 1 molecular proportion ofdiazotized 4=ch1oro2--arni-nr-A lfhydroxybenzene with 1 molecularproportion of 2-hydroxynaphthalene-S.8disulfonic acid',` "be- H n y istransformed by coppering, with splitting up themetvhoxy group, ntothecopper complex compound `of the probable formula:

' and this copper complex compound isthen trans-y formed into thetechnical valuable water soluble for Vdyestufs are obtained; Furtherthe' o-hydroxy--` diazo compounds have only a s'inall ability ofvcoupling,A and for this' reason itisin some cases l, of advantage,V toemploy 'the' ,better coupling o-hydroxyazodyestu free fromlmetalaccording to the process described in Example 1.

Also in cases the o-hydroxyamino compounds, example, 3.3.`dihydroxy4.4`diaminodi phenyl, are difcultly accessible, it is of advantage tostart with the correspondingv alkylethers or acyl "corripounds,` Up todate the splitting upv of the alkoxy groups inazodyestuls is preferably.Vachieved by transforming the'said alkoxy'az" dyestuffs into heavy metalcomplex compounds.

According' to the invention thefheavymetal being attached to' theazod'yestuff' in 'a complex form is removed, wherebythe'hydroxy-azodye-- stuffs-j corresponding to the startingalkoxy-azoalkoxy compounds'fthe' corresponding dyestuifs otherwisevbeing either not lobtainable'or only with a small yield.r The splittingup of the alkoxy groups is then performed by treating with metalcompounds, whereby vthe metal complex compounds are produced. Then,these metal com--v plex compounds are again `transformed into theazodyestuffs free from heavy metals according to the process described.i

:Dyestuffs capable of yielding'metal Vcomplex compounds are ofespecially technicalv value if compound of the o`hydroxyazodyestuffhaving the dyestuffs containing metal are insoluble in water, thedyestuffs free from metal, however, are easily watersoluble and have agood ailinity for the fibre. The dyestuff free from metal is dyed on thefibre, and the dyeing is then aftertreated with metal compounds, wherebythe in- ,solublef metalv complex compoundis-produced Yyieldingii fastdyeing-ori the f ibre. Y

The invention is illustrated by the following examples, without beinglimited thereto:

ExamplemlfH-l grams of the lead compound of the aosalicylicacid havingthe following con are suspendedwater and boiled with 8 grams of sodiumsulfide for a short time, whereby the lead is precipitated in form oflead sulfide. After filtering, -the-dyestuff vfree from metal Aisprecipitated by acidifying the filtrate with hydrochloric acid. Thedyestui 'is ltered and dried. v' It dyes wool yellowish shades which byafter-chroming on thel fibre yield darker yellow shades of goed fastnessto light` andvlfullin'g. y y

Instead ofthe lead compounds also the corresponding'. manganese, iron,cobalt, nickel, z inc,

` cadmiumlor bismuth compoundsmay be used; in

this Ycase the metals may loe-precipitated in form r3() of suldes.` Alsoby Aheating with hydrochloric acid the Ymetals can be removedfromthecomplex l compounds; in this case the dyestui ,is precipitatedand the metals dissolve in formv of hydrochlorides.

salted out bythe addition of common salt.

Example 2.-10 grams of thecomplex copper the following formulaz areboiled'with' 10 grams of sodiumsuliiidein l litre of waterfor a shorttime, wher'eby'the,a reddishbro'wn coloration Yof the copper compoundturnsto Violet. When thel dyestuff has been 'dissolved, the mixtureisfiltered,andthejprecipitated coppersulfide remains on .the filter."The ltra'te contains the kdyestuff 'free frommetal Theo-hydifoxy-azodyestui freer from' metal vis a brown powder whichcan bedyed 'on rthe fibre. By

after-treating `the dyeing. with chromium' com-v pounds reddish-violet'shadesof good f astness toE light andv fulling are obtained.

Example'. 3.-;20 -grams.' 'of` the compiex copper compound, prepared bycoppering the'a'zodyest'ui from 1' molecular proportion of tetrazotized3.3-

' dimethoxy-4-4fdiaminodiphenyl ,and 2 'molecularA f.

proportions kof -,naphthylQ-S-methyl-55pyraolone-8'sulfonic`.acid 'of*the following formula:

NN-'OQCMEH The precipitated dyestuff isfiltered;,; washed,` dissolved inaqueous soda solution` and which is isolated by s'aiung LoutA andacidi'fpying."

are heated in 1 litre of water with 5 cc. of aqueous caustic soda lye of38 B. and 10 grams of crystallized sodium sulde, until the coloration ofthe solution does no more change. After filtering the precipitatedcopper sulde, the dyestuff is isolated from the mixture. Theo-hydroxydisazodyestui free from metal is soluble in Water and dyescotton, silk and viscose yellowishred shades, which by after-copperingyield Bordeaux red shades of good fastness properties.

Example 4.-20 grams of the complex chromium compound `to theo-hydroxyazodyestuff from 1 molecular proportionof diazotized 5-nitro-Z-amino-.l-hydroxybenzene and 1 molecular proportion of2-aminonaphthalene-G-sulfonic acid of the disazodyestui from 1 molecularpropor` tion of tetrazotized 4.4diaminodiphenyl3.3'di carboxylic acid, lmolecular proportion of 2- phenylamino--hydroxynaphthalene 7 sulfonicacid and l molecular proportion of 1-hydroxynaphthalene--sulfonic acidare suspended in hot water and boiled with 10 grams of crystallized-Thereby the difficultly soluble sodium sulde. copper compound istransformed into the easily soluble dyestuff free from metaL'While thecopper precipitates in form of copper sulfide. After filtering thecopper sulde, the dyestuf free from metal is salted out from theiiltrate. It isa dark powder, soluble in Water with a violet-bluecoloration and dyeing cotton bluish-violet shades, which byafter-chroming yield blue dyeings of good fastness properties. l

In an analogous manner the copper can be re-J moved by means of mineralacids, such as hydrochloric acid and sulfuric acid, yor organic acids,such asy oxalic'acid and formic acid., l

1. The process which comprises reacting upon an azodyestui containing aheavy metal in a complex form in solution or suspension Vwith an agentsplitting off the heavy metal from the azodyestui and binding said heavymetal.

,2, 'I'heprocess which comprises reacting upon an azodyestui havinghydroxy groups in the 0.o'- positions to at least one azo groupcontaining a heavy metal in a complex form in solution or suspensionwithl an agent splitting off the heavy metal from the azodyestui andbinding said heavy metal. f

3. The process which comprises reacting upon an azodyestui containing aheavy metal of the group consisting of copper and chromium in a complexform in solution or suspension with an agent splitting oil the heavymetal from the azodyestui and binding the heavy metal. i

4. The` process which comprises reacting upon v vv an azodyestuff havinghydroxy Agroups inthe o.opositions to at least one azo group containiing a metal of the group consisting of copper and chromium in a complexform in solution or suspension with an agent splitting oi the heavymetal from the azodyestuii' and binding the heavy c metal.

5. The process which comprises reacting uponl an azodyestui havinghydroxy groups in the o.opositions to at least one azo groupcontainingcopper in a complex form in aqueous alkaline solutionl orsuspension with sodium sulde.

6. The process which comprises reacting upon an -azodyestui havinghydroxy groups in the RICHARD sTssR.

